1. Field of the Invention
The present invention relates to a punching die, and more specifically to a punching die which can prevent punching noise generated during punching processing of work.
2. Background Art
Generally, the punching processing is effected by moving up and down an upper die against work placed on a lower die. Therefore, whenever the work is punched out, punching noise is inevitably generated. In order to prevent the generation of the punching noise, generally a damping material such as urethane has been provided at the bottom portion of a punch guide for constituting a part of the upper die.
In the general way of providing a damping material such as urethane at the bottom portion of the punch guide, however, there exists a problem in that needle-shaped dust or refuse is inevitably produced during punching processing and further adheres onto the damping material or scratches the surface of the work to be punched out. In addition, there exist other problems in that the damping material is short in life time and difficult to be mounted at the bottom of the punching die.